The phenomenon of chemiluminescence has been known for some time. This phenomenon is the basis of a number of inventions, including novelty items such as light sticks, glow bracelets and necklaces, and light wands, which may be seen at concerts, theme parks, etc. during the early evening and nighttime hours. The usual method of operation of these items is to bend, shake, or otherwise cause an internal, frangible container to break, resulting in the mixing of chemicals which exhibits a chemiluminescence reaction. These items are very inexpensive, and are essentially xe2x80x9cthrow awayxe2x80x9d items, as they cannot be reused. The basis for such items is described in U.S. Pat. No. 3,584,211, which discloses the xe2x80x9clight stickxe2x80x9d, in which a cylindrical container holds one chemical, and an internal, frangible, smaller cylindrical container contains a second chemical. When the cylinder is bent sufficiently, the internal container breaks, allowing the two chemicals to mix, causing the desired reaction. These novelty glow products typically continue to produce light for between 6 and 10 hours after being activated.
Chemiluminescence is used for more serious applications as well. These include safety applications under conditions where power sources, such as batteries, are not appropriate. For instance, divers use items similar to glow sticks to make them visible during night dives.
The present invention combines the light-producing qualities of chemiluminescent devices with the light-retaining qualities of photoluminescent materials. U.S. Pat. Nos. 4,992,302, and 6,008,012 describe methods for making photoluminescent powders, which can be incorporated in other materials, such as plastics, making the plastics themselves photoluminescent. Such materials may continue to glow for up to 10 hours after being exposed to light.
In the present invention chemiluminescent light sticks are combined with photoluminescent plastic to produce illuminated signs which are inexpensive, reusable, and do not require external power sources. As such, they are useful as toys, novelties, and safety devices.
It is an object of the present invention to provide a which contains its own source of illumination, and which is simple and inexpensive to build.
It is a further object of this invention that such a sign be re-usable.
In accordance with one aspect of the present invention, the source of the light is a chemiluminescent light stick.
In accordance with a second aspect of the invention, the light contains a display panel which is impregnated with photoluminescent powder.
In accordance with a third aspect of the invention the display panel has a mask on its face with cutouts through which the light created by the photoluminescent powder may be seen.
In accordance with a fourth aspect of the invention the display panel is part of a cylindrical body with triangular cross section.
In accordance with a fifth aspect of the invention the light stick fits snugly within the body, and is retained therein by friction.
In accordance with a sixth aspect of the invention the mask is formed on the display panel by stamping.
In accordance with an eighth aspect of the invention the mask is formed on the display panel by screening.
In accordance with a final aspect of the invention the body is formed from a single sheet of material impregnated with the photoluminescent powder, which contains tabs and slots to hold the body together when assembled.